(1) Field of the Invention (skill in the art)
This invention relates to oil field equipment and more particularly to a fishing tool for broken sucker rods and specifically a fishing tool for broken composite sucker rods having metal couplings.
People using fishing tools to fish for sucker rods have ordinary skill in this art.
(2) Description of the Related Art
At the present time in oil wells, composite sucker rods are often used. Sometimes composite sucker rods are referred to as fiberglass sucker rods.
Typically composite sucker rods will be made up with joints of a composite rod of about 37 feet in length connected by metal couplings. The metal couplings are typically cylindrical in shape except for wrench flats. Normally they will have wrench flats which will have four faces. I.e., they will form a square. Normally the diagonal of the square will be about the same as or slightly longer than the diameter of the cylinder on which it is formed. Normally a fishing neck is not formed upon the metal coupling of composite rods.
The failure of the fiberglass rod is usually in the fiberglass. Also when the fiberglass fails, it often leaves a splintered end.
Therefore a typical fish for a fiberglass sucker rod will include a long length of fiberglass having an upper portion that is splintered and a coupling without a fishing neck below the broken rod. Somewhere below the broken rod the sucker rod will be stuck within the well. Normally the surface of the sucker rod is such that it cannot be gripped with sufficient tightness to unstick it.
Often times in fishing it is desirable to be able to release the fish or disengage the fish.
Before this application was filed, the applicant was aware of the following U.S. Pat. Nos.:
______________________________________ KINLEY 1,645,010 October 11, 1927 THOMPSON 1,750,248 March 11, 1930 O'BANNON 1,828,938 October 27, 1931 HINDERLITER 1,858,500 May 17, 1932 O'BANNON 1,869,861 August 2, 1932 NEILSON 2,096,525 October 19, 1937 JUSTICE 2,970,859 February 7, 1961 KENNARD 2,973,037 February 28, 1961 WOOLLEY 3,393,002 July 16, 1968 HARBISON 3,549,187 December 22, 1970 WEBB 4,023,847 May 17, 1977 TAYLOR 4,185,865 January 29, 1980 ______________________________________
THOMPSON as early as 1930 had invented a collet type fishing tool for sucker rods.
O'BANNON '861, in 1932 discloses a fishing tool which is commonly on the market today. It may be seen that it has a three fingered collet which is designed to specifically engage a fishing neck of a metal coupling of a metal sucker rod.
HARBISON in 1969 disclosed a particular tool which was designed to engage either a broken metal rod or some particular protruding part of a coupling.
TAYLOR discloses a releaseable wire line overshot using a collet. TAYLOR is releaseable by a cam and ratchet mechanism within the tool itself independent of the fish being caught and/or released.
Applicant does not believe the Examiner would consider the remaining patents relevant or pertinent to the examination of this application but applicant thinks that the Examiner would be interested in what was reported by an experienced patent searcher.